Roll



J. ROCKOFF Sept. 3, 1957 ROLL Filed Sept. 30, 1953 F H' 5 INVENTOR.

JOSEPH ROCKOFF Z,8@4,678 Patented Sept. 3, 1957 ROLL Joseph Rockoif, Dayton, Ohio, assignor to The Dayton Rubber Company, a corporation of Ohio Application September 30, 1953, Serial No. 383,350

15 Claims. (Cl. 29-421) This invention relates to an improved type of rubber roll and to a composition and method for its manufacture. It relates more particularly to rubber rolls especially adapted for the handling of liquids as in coating, inking, gluing, or slashing operations. This invention relates further to a novel type of roll especially adapted for use in the slashing of textile fibers and yarns.

Slashing is an operation used in the textile industry in the application of sizing material to textile fibers and yarns and in particular to cotton, rayon, and artificial silk fibers. Various types of sizing materials are used depending on the type of yarn and the results desired. Starches are generally used in the sizing of cotton yarns; whereas gelatin, soluble starches, and natural gums are most generally used in the sizing of rayon yarns. The sizing material may also include softeners, such as sulphonated oils, and penetrants or wetting out agents. The application of size to the textile yarn makes the yarn smoother and stronger to stand the strain of weaving, eliminates fraying, and facilitates subsequent handling of the yarn.

In carrying out the slashing operation, a number of strands of the work yarn are conveyed in parallel between one or more pairs of horizontal rollers usuallyarranged with a bottom roll at least partially immersed in the sizing liquid and a top roll resting on the bottom roll and driven by the rotation thereof. The yarn may pass between the rolls without immersion in the bath, thus being impregnated by the sizing liquid carried into contact with it by the bottom roller, or in some cases, may pass beneath the bottom roller for immersion in the sizing liquid prior to passing between the two rollers. The bottom rollers are generally made of copper and are gear driven. The top rolls, commonly known as the slasher rolls, are generally constructed of cast iron and are. of considerable weight, usually weighing from 500 to 700 lbs. each. These are normally covered with resilient wool blankets. The function of the wool blanket, by the nature of its resilience and absorptive properties, is to remove excess size from the yarn as it emerges from the bite of the rollers. These blankets possess the necessary resilience and absorptive characteristics to properly dress the yarn to a predetermined proportion of sizing. In the case of cotton yarns, using starch size, this usually runs up to about 16% to 18% based on the weight of the yarn. In general, the slasher roll must have the property of uniformly distributing the size and controlling the proportion which is permitted to remain in the yarn, and must minimize the waste of excess sizing material. Furthermore, the roll surface must be resistant to hot size solutions, such as boiling starch, and must also be resistant to oils and chemicals which may be incorporated with the sizing material. In addition, the roll must prevent flattening of the yarn and leave no roll marks, and must uniformly retain its resilience and absorptiveness over its period of use.

The wool blanket performs its operation satisfactorily but has the disadvantage of cost and short life in service.

Attempts have been made to substitute for the wool blanket, rolls covered with other materials, including synthetic rubber and the like. Such attempts have been only partially successful since such roll surfaces, while more durable than wool, have approached but have not equalled or exceeded its adaptability to the sizing of various types of yarn using various types of sizing material. From the standpoint of durability and ease in fabrication, rubber-containing rolls have been found to otfer great promise, but previous rubber roll compositions and structures, while performing satisfactorily, have not proved to be the complete substitute for the wool blanket.

Rubber rolls having porous and liquid retaining surfaces have also been found to be useful in numerous other applications. Among these are as damper-ductor rolls in lithography inking rollers for applying ink to printing plates or printing rolls, rolls for applying glue or other materials to Various types of surfaces or satisfactory materials for similar applications.

It is therefore an object of the present invention to provide a novel type of porous surfaced rubber roll which is particularly adaptable for all purposes in which liquid materials are to be applied to various types of surfaces.

It is a further object of the present invention to provide a slashing roll having a surface structure which is highly resistant to the sizing material and to the conditions of operation over a long period of time and which will at the same time properly dress the yarn to a predetermined concentration of size.

In accordance with the present invention, it has been found that the improved rolls are obtained by incorporating within a rubber compound, of which the roll surface is formed, two different additional materials. The first of these added materials is composed of frangible, siliceous, glass-like particles. These particles are preferably of an expanded or hollow nature since such particles have been found to be not only frangible when the roll surface is ground, but the broken particles readily evacuate the surface leaving it rough and pitted. Other frangible particles such as sand, glass beads, crushed rock, and the like, may also be used but will require more severe grinding of the roll surface to insure fairly complete removal from the surface.

The second material which has been found desirable to incorporate consists of individual relatively short discrete fibers such as the natural and synthetic textile fibers, including wool, cotton, rayon, Orlon, Dacron, and others described below.

The incorporation of both of these classes of materials has been found to have an unexpected cooperative effect, since these materials used alone in such rolls as slasher rolls and the like have not had the desired results in connection with slashing of fibers and similar applications. It is believed that a roughened surface is obtained by grinding the material having frangible, siliceous particles incorporated therein since these particles are disintegrated and removed from the surface leaving a roughened and pockmarked texture. However, this alone is not enough and a further modification of the surface is required by the exposure of the fibers which remain embedded but exposed at the surface.

The hollow, frangible particles to be incorporated within the article of the present invention are preferably smooth surfaced and of such size and structure that, while they are embedded in the rubber composition, they will resist the forces acting therein and will accordingly remain substantially whole and unbroken until they are exposed at the surface-contacting portion of the article by grinding at which time they will be easily broken. Particles such as these, because of their smooth surface, will have no abrasive, wearing, or deteriorating effect upon the rubber composition while the particle remains completely embedded therein; whereas, upon being exposed to the surface-contacting portion of the article, the hollow, frangible ingredient can be broken to provide an irregular and porous surface.

It has been found that particles particularly adaptable to the present invention are composed of a refractory composition such as fused argillaceous or siliceous materials. Such materials in the form of small spheroidal or similar smooth-surfaced shapes have been found especially satisfactory for the purposes of the present invention in that they are sufiiciently hard and durable to resist breakage while remaining within the rubber-like material but, at the same time, are sufiiciently brittle to fracture upon exposure to the articles wearing surface. The spheroidal particles referred to herein and which are incorporated as a component of the rubber compounds referred to, are obtained by the fusion of argillaceous materials such as clays and shales, under such conditions that finely divided, hollow, spheroidal or substantially spherical particles are obtained. These particles are obe tained by feeding the ground and screened clay into the top of a vertical furnace. The individual grains of the raw material fall through a gas-air flame at a temperature of about 2700 F., become fused, and cool during the remainder of their fall. They are then collected at the bottom of the furnace. The resulting particles are smooth, hollow and almost spherical and possess sufficient strength to permit compounding with rubber by milling or otherwise without breaking. These particles may range in size from about 0.20 in. in diameter down to about 0.001 in. in diameter. The resultant particles are, in effect, expanded glass or glass-like materials. In place of glass or similar argillaceous material, particles of silica or sand or complex silicates or minerals in the form of ground rock might also be utilized.

The second materialwhich is to be incorporated within the rubber compound referred to is composed of short fiber particles of either natural or synthetic fibers, including Dacron (commonly designated as terephthalate compounds a specific example of which is the product made by the condensation of dimethyl terephthalate and ethylene glycol), acrilan or Orlon (polyacrylonitrile), nylon (polyhexamcthylene adipamide), rayon, vinyon (vinyl-chloride/vinyl-acetate), casein or other protein fibers (Vicara), cotton, wool, etc., the above fibers being intended to include both natural and synthetic textile fibers.

These fibers are obtained in short lengths by cutting, chopping, grinding, or otherwise, with the majority of fibers preferably in lengths ranging from to /2 in. and are incorporated into the rubber compound containing vulcanizing and other desired compounding ingredients along with the frangible particles referred to above, by milling or otherwise. The resulting product is then formed into sheets and applied to a roll as a cover therefor, after which the roll is rag wrapped and vulcanized. The vulcanized roll is then ground at its surface to rupture and remove particles of the embedded frangible material while at the same time exposing the incorporated fibers. The frangible particles and textile fibers are effective in greater or less degree in all proportions. In general, a preferred range of proportions for the frangible particles is from about to 200 parts by weight for each 100 parts of rubber, while the fibers are preferably incorporated in the proportion of about one to parts by weight per 100 parts of rubber.

The rolls referred to may be composed entirely of the novel composition referred to, but it is frequently preferred to utilize this material as a sleeve or roll covering material with the base or intermediate layers being of other rubber composition or any desired material.

The structure of the resultant product is illustrated in the accompanying drawing, wherein:

Figure 1 illustrates a view in perspective of a finished roll of the present invention.

Figure 2 illustrates a view in vertical cross section taken along lines 22 of Figure 1.

Figure 3 is a vertical cross sectional view corresponding to Figure 2 but before the final grinding operation is carried out.

Figure 4 illustrates a partial cross sectional view of one of the hollow, frangible, siliceous particles.

Figure 5 is an enlarged cross sectional view of a portion of the surface layer of the roll showing the internal structure thereof.

Referring now to Figures 1 to 3, roll 10, which may be a slasher roll or other roll for handling liquid materials, is formed by positioning a sleeve 11 upon a metal Shaft or core 12, said sleeve being composed of a rubber composition of a desired degree of hardness. The surface of the roll consists of a covering layer or sleeve 13 which is composed of the novel composition of this invention.

Figure 4 illustrates one of the hollow, frangible particles 14 which are incorporated into the roll covering composition.

Figure 5 illustrates the roll covering composition 13 showing the frangible particles 14 and fibers 15 dispersed therein. This figure clearly illustrates the surface porosity which is created by the total or partial removal of the frangible particles thereby leaving surface openings or pores 16. The grinding operation also exposes certain of the fibers 15 as shown.

A typical rubber composition used in making rolls of the present invention is as follows:

Parts by weight Butadiene-acrylic nitrile copolymer (Hycar) (55 parts butadiene45 parts acrylic nitrile) Frangible, hollow, siliceous particles (30 mesh) Dacron fiberscut staple 3 denier random lengths Plasticizer (tricresyl phosphate) The composition was prepared in a conventional man- H ner, with the siliceous particles and fibers being intimately dispersed into the rubber along with the other compounding ingredients by milling.

A series of comparisons was carried out in wh ch slasher rolls formed of compositions of the present invention were compared with slasher rolls of other compositions under identical operating conditions. The comparisons were carried out in a standard slashing apparatus deslgned for laboratory or pilot plant use and differ from the standard commercial equipment only in the length of the slasher roll to permit utilization of less space and material. All the slasher rolls utilized were fabricated upon cores 6 /8 in. in diameter, each core being covered with'a layer of an oil-resistant butadiene-acrylic nltrile copolymer about Vs in. in thickness. This intermedlate layer was then covered with a sleeve composed of the novel slasher roll composition of the present invention or of the composition to be evaluated for purpose of comparison A in. in thickness. This sleeve was adhered by means of cement to the intermediate layer. The rolls were then utilized in the slashing of cotton yarn in a standard sizing bath containing starch, tallow, emulsifying oils, natural gum, and water at 212F. The diameters of the finished rolls were 8% in. and the length of each was 8 in.

The slashing characteristics of these rolls were then compared with the characteristics of a conventional slasher roll covered with wool blankets and each comparison is tabulated below. Each roll was run continuously in this slashing bath for 200 hours consecutively, with a sample of yarn being run through every 50 hours. The

5 comparisons were made by conducting a desizing analysis of each sample of sized yarn, the objective being to achieve as nearly as possible the sizing concentration achieved by the use of wool blanket covered rolls. This is commonly accepted as the standard by the industry.

Percent Percent size on Roll No. Roller Composition Size on yarn, yarn Wool control Buna-N 16 12 Buna-N 120 pts. by wt. frangible 16.5 12

particles per 100 pts. rubber. Buna-N 120 pts. frangible particles 9. 7 9. 5

25 pts. Dacron fiber per 100 pts. rubber. d 10.5 10.8 -.--do 10.8 10.4 Buna-N 120 pts. frangible particles 14.35 14. 1

25 pts. Orlon per 100 Eta. rubber. Buna-N 120 pts. frangi ie particles 13.55 14. 7

25 pts. Vieara per 100 pts. rubber. Buna-N 120 pts. frangible particles 12. 75 12.6

+ 25 pts. Acrilan per 100 pts. rubber.

As indicated above, roll No. 1 is of a plain Buna-N composition compounded substantially in accordance with the recipe described above, but omitting the frangible particles and fiber. Roll No. 2 was of the same composition as the above recipe except that the fibers were omitted although the frangible particles were included. Rolls Nos. 3, 4 and 5 were of the exact composition as the recipe referred to above including the frangible particles with Dacron fibers. These were run with three different samples of the yarn and three difierent times. Rolls Nos. 6, 7 and 8 represent the results obtained in accordance with the present invention substituting other fibers; namely, Orlon, vicara and acrilan, respectively, for the Dacron, with the frangible particles. The table clearly indicates that the incorporation of both the fibers and the frangible particles gives sizing results very closely comparable with those obtained by the use of wool. The results obtained in the laboratory equipment were verified by installing rolls of a corresponding composition in a large textile mill where their performance was observed under actual production conditions. After three months of operation these rolls were performing as well as corresponding wool covered rolls without loss of sizing efficiency or excessive wear.

The term rubber as used herein is intended to include both natural and synthetic rubbers. By the term synthetic rubbers is meant the synthetic elastomers having the properties of resilience, elasticity, and vulcanizability similar to those possessed by natural rubber. The synthetic rubbers in general include the rubber-like polymers of conjugated diolefins and their copolymers with styrene, acrylic nitriie, and other monomers known to be copolymerizable therewith. The synthetic rubbers also include the chloroprene polymers known as neoprene, the iso-olefindiolefin copolymers known as butyl rubber, and the polysulfide polymers known as 'I'hiokol. In applications where the rolls are exposed to extreme conditions of temperature, oils, and the like, it is preferred to use the oil resistant types of synthetic rubber, such as neoprene, and the butadiene-acrylic nitrile copolymers, such as Hycar OR, and/or Buna-N.

I claim:

1. A roller having a porous and roughened surface for the application of liquid materials comprising a surface layer of a vulcanized rubber composition having dispersed therein hollow, frangible, siliceous particles and discrete textile fibers.

2. A roller according to claim 1 wherein the rubber composition comprises an oil-resistant synthetic rubberlike material of the butadiene-acrylic nitrile copolymer type.

3. A roller according to claim 1 wherein the textile fibers comprise a synthetic textile fiber material.

4. A roller according to claim 3 wherein the textile fiber is Dacron.

5. A roller according to claim 3 wherein the textile fiber is a synthetic polyacrylonitrile fiber.

6. A roller according to claim 3 wherein the textile fiber is a protein fiber.

7. A slasher roll for the controlled application of sizing material to textile fibers and yarns which comprises a surface layer of a rubber composition having incorporated therein a substantial proportion of hollow, frangible, siliceous particles and textile fibers.

8. A slasher roll according to claim 7 wherein the textile fibers are Orlon.

9. A slasher roll according to claim 7 wherein the textile fibers are Dacron.

10. A slasher roll according to claim 7 wherein the textile fibers are Acrilan.

11. A slasher roll according to claim 7 wherein the textile fibers are vicara.

12. A slasher roll comprising a surface layer of a vulcanizable rubber composition having dispersed therein from about 10 to 200 parts by weight of hollow, frangible, siliceous particles per parts by weight of rubber composition and from about one to 50 parts by weight of textile fibers per 100 parts by weight of rubber composition.

13. A slasher roll according to claim 12 wherein the frangible particles consist of fused, hollow, clay particles.

14. A slasher roll according to claim 7 wherein the exposed outer surface of said roll contains exposed fibers and surface cavities conforming to removed siliceous particles.

15. As a new composition of matter a rubber composition having a porous surface which comprises a vulcanized rubber composition having initimately dispersed therein textile fibers and particles of hollow, frangible, siliceous material, the surfaces of said composition having textile fibers exposed thereon together with surface openings in the form of such siliceous particles.

References Cited in the file of this patent UNITED STATES PATENTS 1,940,528 Bond Dec. 19, 1933 1,950,621 Morse Mar. 13, 1934 2,569,546 Treue Oct. 2, 1951 2,600,461 Backus June 17, 1952 2,617,129 Petze Nov. 11, 1952 2,638,457 Gates May 12, 1953 2,643,234 Backus June 23, 1953 FOREIGN PATENTS 610,170 Great Britain Oct. 12, 1948 764,663 France Mar. 12, 1934 

